The present invention relates to surgical instruments of jaw-structure and methods for sealing of vessels and tissues, and for welding and coagulation of tissues by utilizing electromagnetic energy.
Conventional open and laparoscopic procedures typically involve sealing of vessels and tissues, as well as for welding and coagulation of tissues. Conventional devices apply electromagnetic energy in microwave or radio frequency range directly to the vessels or tissues. As used herein, “microwave frequency range” refers to frequencies between 30 MHz and 30,000 MHz inclusive, where MHz is one million Hertz, and the term “radio-frequency range” refers herein to frequencies between 30 kHz and 30 MHz, where kHz is one thousand Hertz.
A preferred method of tissue-sealing in prior art relies on capturing the tissue in a jaw-structured instrument and applying electromagnetic energy to the captured tissue to cause thermal effect that results in sealing of the tissue. Various mono-polar and bi-polar radio-frequency (RF) jaw structures have been developed for these purposes, such as presented in U.S. Pat. Nos. 5,462,546; 6,030,384; 5,527,313; 6,926,716; 6,887,240; and 5,528,006, the contents of each of which is incorporated herein by reference.
In conventional systems, the jaw structures that engage opposing sides of the captured tissue volume fail to allow for uniform distribution of heat in the tissue. That is, as the initial amount of RF energy applied to the issue, an associated heating of the tissue surface results and the surface accordingly becomes desiccated and resistant to the additional ohmic heating. The efficiency of the conversion of the RF into heating energy substantially decreases. With such devices, localized tissue desiccation and charring can occur almost instantly as tissue impedance rises. The consequence of such uneven distribution of heat can be non-uniform sealing of the tissue. The typical conventional jaw structure that utilize RF energy can cause further undesirable effects as a result of RF energy propagating laterally from the captured tissue, thus causing unwanted collateral thermal damage.
A conventional jaw structure that utilizes microwave energy (see, e.g., U.S. Pat. No. 6,224,593, the contents of which is incorporated herein by reference), apply this energy directly to the treated tissue. Since it is difficult to control the depth of the microwave energy propagation in the tissue, as well as the increase of the temperature in a particular area of the tissue, which causes non-uniform sealing of the tissue and unwanted thermal damage to the unwanted tissue.
The disadvantages of conventional devices make it desirable to provide a jaw structure for vessels and tissue sealing that is powered by an electromagnetic energy source to transmit energy to minimize a period of time necessary for reaching the desired temperature.
It is also further desirable to provide a jaw structure for vessel and tissue sealing configured with selective electromagnetically-energy-absorbing areas to target sealing areas while minimizing heat exposure to unwanted tissue.
It is therefore desirable to provide a jaw structure for vessel and biological tissue sealing that allows for a relatively brief treatment in a safe and target-oriented manner.
Accordingly, the present invention addresses at least the above-described problems and/or disadvantages and provides at least the advantages described below. An aspect of the present invention provides a jaw structure and method for vessel and tissue sealing, as well as tissue welding and coagulation.